Automatic high speed counting and packaging apparatus of the general type considered here are used routinely by pharmaceutical manufactures to package predetermined quantities of pills, tablets, capsules and similar discrete dosage forms. To meet the requirements of the pharmaceutical industry, such apparatus must be capable of rapidly filling a large number of containers, typically on the order of one hundred to several hundred containers per minute, with a quantity of product which corresponds to the predetermined quantity. In addition, the apparatus should be able to accurately distinguish chipped, broken or otherwise damage product from intact product and segregate containers containing damage product for additional processing. Finally, since automatic counting and filling apparatus are typically used to package several different products, the machine should be designed such that it can be easily disassembled, thoroughly cleaned and reassembled in order to minimize down time. In this connection, the machine should also be designed so that product changeover requires only minimum parts substitution.
Several different types of automatic counting and packaging apparatus are currently available. Slat counters, perhaps the fastest devices of this type, include slats fitted onto a moving chain which rotates the slats through a hopper containing tablets or capsules. The slats have a predetermined number of cavities corresponding to the predetermined quantity of product to be packaged, and each cavity is filed with, for example, a table as the slat rotates through the hopper. As each slat is moved to an unloading position, the predetermined number of tablets are directed into a container. While such a device is capable of filling up to four hundred containers per minute, the down time required for cleaning the device and adapting it for a different product size, shape or predetermined quantity is substantial. This is so primarily because different product sizes and quantities require that every slat in the device be changed. Thus, in addition to the considerable down time associated with cleaning and product changeover, devices of this type require an inventory of many sets of different slats.
Disk counters are another type of commercially available automatic counting and filling apparatus. These devices include a rotating disk which has a series of holes to hold tablets, capsules or similar products. The holes are filled with product in one area of the device, and as the disk rotates to another part of the device, the product falls out of the holes and is diverted into a container. As in the case of the above-described slat counter, the disk counter is difficult to clean and a change in either product size or quantity requires that the disk be changed, which in turn results in significant down time for the device.
Counters are also known which continuously drop product from a hopper onto a vibrating feed tray which advances the product downstream to a photosensor for counting. When a quantity of product equaling the predetermined quantity has been counted by the photosensor, the product is directed into a container. Such devices present a number of disadvantages. First, a considerable distance must be provided between the hopper and the photosensor to ensure that the feed tray has singularized or separated the product sufficiently to be counted. Second, the photosensor typically found in such devices is an opposed beam photoelectric sensor comprising a light source and an opposed receiver. When an object passes in front of the sensor, the beam is interrupted, thus signaling a controller to count the respective object. Because these sensors typically lack the requisite sensitivity, they cannot sufficiently distinguish between products of different size. Thus, the sensor is unable to consistently differentiate between damaged or defective product and intact product. On the other hand, such devices may be so sensitive that they are incapable of differentiating between the objects to be counted and other loose debris or particles, such as chips from damaged product and dust. Thus, the filled container too frequently contains damaged product and a quantity of product which does not correspond to the predetermined amount.
It is, therefore, an object of the present invention to provide a counting device that rapidly separates and accurately counts predetermined quantities of discrete objects, such as tablets and capsules.
It is a further object of the present invention to provide such a device the consistently distinguishes between damaged and undamaged product.
It is yet another object of the invention to provide an automatic, high-speed counting and packaging apparatus for packaging predetermined quantities of discrete objects.
It is a still further object of the invention to provide such an apparatus which is easily cleaned and which can be quickly adapted to count and package different predetermined quantities of products of varying size and shape.